The core network of an evolved packet network includes mainly such three logical function entities as an MME (mobility management entity), an S-GW (serving gateway), and a P-GW (packet data network gateway). The MME is responsible for NAS (non-access stratum) signaling, NAS signaling encryption, roaming and tracking functions, allocation of temporary user identities, and security function. The MME corresponds to a control plane part of an SGSN (serving GPRS support node) inside a UMTS (universal mobile telecommunications system). The S-GW is responsible for local mobility anchor points, mobility anchor points in the 3GPP (the 3rd Generation Partnership Project) system, and lawful interception of related information. The P-GW is responsible for policy execution, charging, and lawful interception of related functions.
A PDN (packet data network) connection is a collection of one or multiple bearers with the same access point name. The first bearer created in the PDN connection establishment process is called a default bearer. If the default bearer is deleted, the PDN connection is deemed to be deleted.
A CSID (Connection Set Identifier) identifies a set of PDN connections inside one node. A set of PDN connections or PDP connections may belong to different user equipments.
An FQ-CSID (Fully Qualified Connection Set Identifier) globally identifies a CSID and is the combination of a CSID and the identifier of a node assigning the CSID. The same CSID may be assigned to different nodes. The FQ-CSID identifies the same CSID assigned to different nodes.
When a network device (MME or SGSN) encounters a fault, the network device sends the FQ-CSID of the faulty network device to an S-GW by using a connection deletion request message. The S-GW forwards the received connection deletion request message to a P-GW, where the message includes the FQ-CSID of the network device. After receiving the connection deletion request message, the P-GW retrieves PDN connection context based on the received FQ-CSID of the network device, confirms and deletes the affected PDN connection from the local, and then returns a connection deletion response message to the S-GW. The S-GW retrieves PDN connection context based on the received FQ-CSID of the network device, confirms and deletes the affected PDN connection from the local, and after receiving the connection deletion response message from the P-GW, returns the connection deletion response message to the network device.
During the implementation of device fault processing, the inventor finds that the prior art has at least the following problems: The network device, S-GW, and P-GW locally delete PDN connections corresponding to the FQ-CSID of the network device synchronously, but a user does not know that the PDN connections have been deleted. Within the period from deletion of the PDN connection to the user's active communication with the network, all services of the user equipment related to the deleted PDN connection are unreachable, which severely affects user's service experience.